Film feed mechanism for a wrapping machine

ABSTRACT

This disclosure deals with a film feed mechanism for an automatic wrapping machine including a wrapping mechanism for wrapping each article of a series of articles in a thin protective film. The feed mechanism draws film from a film supply and feeds it to the wrapping mechanism which is constructed to pull film thereto as needed during each wrapping cycle. In the feed mechanism, film is trained around a stripper roll, through means for tensioning the film and forming a reserve supply loop, and then to the wrapping mechanism. A continuously moving drive member extends adjacent the stripper roll, and a driven member connected to the stripper roll is adapted to be drivingly engaged by the drive member in order to turn the stripper roll. Means responsive to the length of film in the reserve supply loop is connected to move the drive member into engagement with the driven member and thus turn a stripper roll when the length of film in the supply loop is depleted, and to move the drive member out of engagement with the driven member when the length of film in the supply loop is replenished.

Q l hate: States Patent 1 3,59 1,065

I72] Inventors Omar HansenJr. Primary Examiner-Allen N Knowles Yardley,Pm; Attorney-Hibben, Noyes & Bicknell Donald K. Shannon, Poneto Ind. 211Appl. No. 813,150 [22] Filed Apr. 3, i969 l l Patented y 1971 ABSTRACT:This disclosure deals with a film feed mechanism l l Assignee Dovefor anautomatic wrapping machine including a wrapping Fallslngmni mechanismfor wrapping each article of a series of articles in a thin protectivefilm. The feed mechanism draws film from a film su ply and feeds it tothe wrap ing mechanism whichis [S4] g i MECHANISM FORA WRAPPING construeted to pull film thereto s needed during each E 7 D win E S. wrappingcycle. In the feed mechanism, film is trained around m g g a stripperroll, through means for tensioning the film and [52] [1.5. Cl 226/25,forming a reserve supply loop, and then to the wrapping 226/37. 226/44mechanism. A continuously moving drive member extends ad- [5 l 1 int. ClB65h 23/18 jacent the stripper roll, and a driven member connected tothe [50] Field Of Search .4 226/37, 25, stripper roll is adapted to bedrivingly engaged by the drive 240 member in order to turn the stripperroll. Means responsive to the length of film in the reserve supply loopis connected to [56] Refemncesclled move the drive member intoengagement with the driven UNITED STATES PATENTS member and thus turn astripper roll when the length of film in 1,801,739 4 1931 Gustafson226/37 the supply loop is de lete and to move the drive member out 955713 4/1934 T i 226/191 of engagement with the driven member when thelength of 2,200,328 5/ l 940 Cohn et al. 226/37 film in the supply loopis replenished.

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PATENTED JUL slam 3591065 SHEET 2 BF 3 FILM FEED MECHANISM FOR AWRAPPING MACHINE Wrapping machines of the character disclosed inapplication Ser. No. 363,954, now US. Pat. No. 3,432,987 to Hansen etal. have been provided, which include a wrapping mechanism for wrappingan article in film, and a film feed mechanism for feeding film to thewrapping mechanism as needed. The feed mechanism includes means forminga reserve supply loop of film, and the wrapping mechanism pulls filmfrom the loop during each wrapping cycle. A drive motor is connecteddirectly to a roll of film and turns the roll in order to feedadditional film into the reserve supply loop when the quantity of filmin the loop is depleted. A motor control mechanism is provided whichresponds to the quantity of film in the loop and intermittently turnsthe drive motor on and off in order to maintain the quantity of film inthe loop within predetermined limits.

While the foregoing mechanism works well, it has the disadvantage thatit requires a separate drive motor and electrical control for turningthe film supply roll, in addition to the main drive motor for the otherparts of the wrapping machine. A wrapping machine of the characterdisclosed in U.S. Pat. No. 3,248,848 to Littlefield has been provided,which does not include a separate drive motor for the film feedmechanism, but the Littlefield machine includes a relatively complicatedand expensive clutch which is subject to wear and failure.

In accordance with the present invention, the foregoing dis advantagesare avoided by providing a wrapping machine including means forsupporting a supply of film, a rotatably mounted film stripper roll,movable means for holding the film under tension and for forming areserve supply loop in the film, a wrapping mechanism for wrapping anarticle in film and pulling film from the loop as needed during eachwrapping cycle, the film extending from said supply, about said stripperroll, about said movable means and to said wrapping mechanism,continuously moving drive means extending adjacent said stripper roll,driven means connected to said stripper roll and adapted to turn saidstripper roll when engaged by said drive means, and actuator meansconnecting said movable means and said drive means and adapted to movesaid drive means into and out of engagement with said driven means uponmovement of said movable means such as to maintain the length of film insaid loop within predetermined limits.

Other advantages and objects of the invention will become apparent fromthe following detailed description taken in conjunction with theaccompanying figures of the drawings, wherein:

FIG. 1 is a side elevational view of a wrapping machine including a filmfeed mechanism embodying the invention;

FIG. 2 is an enlarged fragmentary view of a portion of the wrappingmachine, showing in greater detail the film feed mechanism;

FIG. 3 is a further enlarged fragmentary view taken on the line 3-3 ofFIG. 2;

FIG. 4 is another further enlarged fragmentary view taken on the line4-4 ofFlG. 2;

FIG. Sis a fragmentary view taken on the line 5-5 of FIG. 4;

FIG. 6 is a fragmentary sectional view taken on the line 6-6 of FIG. 2;and

FIG. 7 is an enlarged fragmentary sectional view taken on the line 7-7of FIG. 2.

With reference to FIG. 1, the wrapping machine comprises a frame 10which is supported by a base 11, the base 11 in turn being supported onthe floor by wheels 12 which permit the wrapping machine to be readilymoved on the floor when desired. The base 11 may alternatively besupported on the floor by adjustable legs 13 which take the weight offthe wheels 12 when the wrapping machine is in use so that the wrappingmachine can not move on the floor. The frame 10 includes a pair oflaterally spaced, vertically extending side plates 10a and 10b (FIGS. 1and 6), and mounted between the side plates is a wrapping or foldingmechanism of the general character described in the above mentionedHansen et al. patent application. Briefly, the wrapping mechanismcomprises a pair of vertically movable elevators 14a and 14b (FIG. 1), adancer roller 15, and a draper or forward roller 15a. An article infeedconveyor 16 pushes an article forwardly onto the elevator 14b, andrelative movements of the elevators 14a and 14b and the dancer roller15, transfer in the rearward direction of the article from the elevator14b to the elevator 14a, and transfer of the article from the elevator14a to a plate 17a result in folding of a section of film 20 around thearticle. The plate 17a is part of an end folding and sealing mechanism17, and the article is then moved forwardly through the mechanism 17 andout ofthe machine. A main drive motor 18 which is continuously energizedwhile the machine is in operation, is mounted on the base 11 and isconnected through a belt and gear speed reducer 19 to a transverselyextending drive shaft 21. A plurality of cams, linkages and chains (notshown) connect the drive shaft 21 to operate the elevators and the otherparts of the wrapping machine. The wrapping mechanism pulls or drawsfilm 20 to itself as needed in each wrapping cycle, and a film feedmechanism 22 supplies the film 20 to the wrapping mechanism.

The wrapping machine further includes a vertically extending mountingplate 26 (FIGS. 1 and 6) which is located at one side of the wrappingmachine adjacent the plate 10a, the plate 26 being rigidly secured tothe plate 10a by a plurality of bolts 27 (FIGS. 2 and 6). A spacer 28 ispositioned between the plates 26 and 10a around each bolt 27 in order tohold the plate 26 spaced from the plate 10a. A plurality of arbors 29,30 and 31 are rotatably mounted on the plate 26, the arbors 29, 30 and31 being adapted to support film supply rolls 29a, 30a and 31a (FIG. 1).While only one roll is used at a time, it is preferred that more thanone arbor be provided so that rolls of different width film, ordifferent kinds of film, may be provided on the machine at one time.With reference to FIG. 2, a brake is preferably provided to prevent eacharbor from turning too freely, and in the present instance each brakecomprises a strap or belt 33 which has one end anchored as at 34 to theplate 26 and its other end fastened to a tension spring 36, each belt 33being looped about the associated arbor. An adjustable bracket 37 isprovided to fasten the spring 36 to the plate 26, the bracket 37 beingconnected to the plate 26 by a bolt 38 which extends through anelongated slot 39 formed in the bracket 37. Thus, to increase the amountof drag or braking force on an arbor, the bolt 38 associated therewithis loosened and the bracket 37 is shifted toward the left as seen inFIG. 2 in order to increase the tension in the spring 36. Of course,movement of the bracket 37 in the opposite direction serves to decreasethe tension in the spring 36 and therefore to decrease the amount ofdrag on the arbor. The brakes for the three arbors are shown only inFIG. 2 for the sake of clarity in the drawings.

With reference to FIG. 6, each arbor comprises an elongated tubularmember 40 which is rotatably mounted on the plate 26 in cantileverfashion. A mounting tube 41 which is rigidly secured to the plate 26extends into one end of the member 40, and the tube 41 forms the innerrace of a ball bearing 43 rotatably connecting the tube 41 with theinner periphery of the member 40. Extending laterally inwardly from thetube 41 and rigidly secured thereto is a stub shaft 44 which supports asecond ball bearing 46, the bearing 46 also being connected to the innerperiphery of the member 40.

Film of the type used with the wrapping machine is supplied as anendless sheet which is rolled on a tube in conventional fashion. Toreleasably secure such a roll of film to the arbor 29, a shoe 47 ispivotally mounted within the interior of the member 40 such that theshoe may be moved through a slot 62 into or out of binding engagementwith the tube on which the film is wound. The shoe 47 is pivotallysupported at approximately the center of the member 40 by a pin 48 whichconnects the shoe 47 with an axially extending rod 49. A plate 51 ispositioned within the opposite end of the member 40 from the tube 41 andis secured thereto as by a set screw or pin 52,

and the adjacent end of the rod 49 is secured to the plate 51. To pivotthe shoe 47 about the pin 40, a second rod 53 is provided, one end ofthe rod 53 being rotatably supported by the plate 51 and the other endof the rod 53 being supported by a bracket 56 which is fastened to therod 49. The rod 53 extends through the plate 51 and is fastened to aknob 54 which is located beyond the end of the member 40. The end of therod 53 adjacent the bracket 56 is threadedly connected to a sleeve 58which is pivotally connected to the shoe 47 by another pin 59. Thus,when the knob 54 is manually turned, the threaded sleeve 50 is movedtoward or away from the bracket 56, thereby causing the shoe 47 to pivoton the pin 48. The outer edge 61 of the shoe 47 extends through the slot62 in the wall of the member 40, and when the shoe 47 is pivoted in theclockwise direction as seen in FIG. 6 by turning the knob 54in onedirection, the edge 61 swings outwardly into binding engagement with thefilm supply roll. To release the film supply roll, the knob 54 is turnedin the opposite direction to retract the shoe 47.

As previously mentioned, the other two arbors 30 and 31 preferably havea construction identical with that of the arbor 29.

In the film feed mechanism 22 (FIGS. 1 to 3), the film 20 from a supplyroll, such as the roll 29a, is trained upwardly and looped over the topofa freely rotatable roller 64 (FIGS. 2 and 6), then underneath andaround the rearward side of a stripper roll 66, then forwardly and abouta tension roller 67, then rearwardly and underneath a freely rotatableroller 60, then upwardly and about another freely rotatable roller 69,and then rearwardly to the draper .roll a and the wrapping mechanism. Afilm check valve 63 (FIG. 1) prevents the film from being pulled backinto the film feed mechanism 22.

The roller 64 is rotatably connected between the plates 26 and 10b. Thetwo rollers 60 and 69 are connected, at one end. to a bar 71 (FIGS. 2and 6) which extends vertically upwardly from the plate 26 and issecured thereto by bolts 72. The other ends of the two rollers 60 and 69are rotatably connected to the side plate 10b of the frame 10 (FIG. 6).

The stripper roll 66 (FIG. 6) is also rotatably connected to the plates26 and 10b, and comprises a tubular member 79 having end plates 81 and02 positioned within the ends thereof and secured thereto as by setscrews. A shaft 76 extends through the member 79 and through holes inthe plates 01 and 32, and at least one of the two end plates 01 and 02is fastened to the shaft 76. The shaft 76 is rotatably connected to theplates 26 and 10b by bearings 77 and 70, respectively. At spacedlocations along the length of the member 79 are a series of frictionbands 03 which are made of silicone sponge. Some types of film aresupplied by the manufacturer thereof with a light dusting or coating orpowder, and it has been found that friction materials other thansilicone sponge become clogged with the powder and quickly lose theirfrictional properties. The bands 03 frictionally grip the film 20 andpull it from the supply roll 29a when the stripper roll 66 is turned. Asis best shown in FIG. 2, the roller 64 is mounted relatively close tothe portion of the film 20 between the roll 66 and the tension roller 67so as to provide a relatively large area of contact between the film 20and the bands 03. The roller 64 also ensures that this area of contactis the same regardless of the arbor from which the film is being drawn.

The shaft 76 of the stripper roll 66 extends through an opening formedin the plate 26 and into the space between the plates 26 and 10a, andhas a sprocket 06 connected thereto. The connection between the sprocket06 and the shaft 76 is preferably through a one-way clutch 07, for areason to be described hereinafter, and the sprocket 86 is adapted to bedriven from the drive shaft 21 by a chain 80 (FIGS. 1 and 2).

The tension roller 67 is rotatably mounted on the upper ends of a pairof laterally spaced tension arms 91 (FIGS. 2, 4 and 6) which extenddownwardly from the tension roller 67 and are secured to the oppositeends of a laterally extending support rod 92. The rod 92 also extendsthrough an opening 95 (FIG. 7) formed in the plate 26 and is rotatablysupported on the plate 26 by a bearing 93. To fasten the bearing 93 tothe plate 26, the housing of the bearing 93 has an annular flange 97(FIG. 7) formed thereon, which is positioned against the inner face ofthe plate 26, and a square-shaped bearing ring 98 (FIGS. 2 and 7) ispositioned tightly against the flange 97 and secured to the mountingplate 26 by a plurality of bolts 99 (FIG. 2). The two arms 91 areangularly biased in the clockwise direction as seen in FIGS. 1 and 2 bya coiled torsion spring 94 (FIGS. 4, 6 and 7), the inner end of thespring 94 being attached to the rod 92 and the outer end of the spring94 being anchored to a pin 96 (FIG. 7) which is secured to the housingof the bearing 93. The amount of force exerted by the spring 94 may beadjusted by loosening the bolts 99 and turning the housing of thebearing 93, and thus the outer end of the spring 94, relative to theplate 26 and the rod 92.

When film from a supply roll supported by either of the arbors 30 or 31is being used, the film extends from the supply roll, through theopening (FIG. 6) formed between the arms 91, the roller 67 and the rod92, to the roller 64.

A clutch is provided to move the chain 08 into and out of engagementwith the sprocket 06 in response to angular movement of the arms 91 andthe rod 92. To this end, a track arm 101 (FIGS. 4, 5 and 7) is fastenedto the end of the rod 92 which is adjacent the sprocket 06, and extendsradially from the rod 92. To fasten the arm 101 to the rod 92, alaterally extending hole is formed in the rod 92 to receive the trackarm 101, and a set screw 102 threaded into an axially extending hole inthe rod 92 secures the arm 1011 to the rod 92. A roller 103 is rotatablyfastened to the outer end of the arm 101 by a bolt 104. The roller 103extends parallel to the rod 92 and toward the plate 26, and is locatedgenerally below the sprocket 06 and the chain 88 (FIG. 5).

The clutch further includes a chain guided assembly 106 (FIGS. 3 to 5)slidably engaging the chain 00 adjacent the sprocket 06. In the presentinstance, the chain is a roller chain and includes two rows of links109, the two rows being separated by rollers (FIG. 4). The assembly 106comprises an elongated upper track 107 which has a width slightly lessthan the distance between the two rows of links 109 of the chain 80 sothat the track 107 is able to ride on the rollers 100. The upper track107 is supported by a track plate 111 (FIG. 3) which is pivotallyfastened to the plate 26 by a bolt 112. Washers 1113 on opposite sidesof the track plate 111 permit the plate 111 to freely pivot on the bolt112. The upper track 107 is fastened to the plate 111 by a plurality ofscrews 114 (FIG. 3), and a tubular spacer 116 is provided around eachscrew 1114 to hold the track 107 spaced from the plate 111.

On the underside of the chain 00 and also connected to the track plate111 are a pair of spaced apart lower tracks 1117 and (FIG. 5) which arepositioned on opposite sides of the sprocket 06. The lower tracks 117and 110 are fastened to the plate 111 by screws 119, and spacers 121(FlG. 4) hold the lower guides 117 and 110 in spaced relation from theplate 111. The tracks 117 and 110 are the same width as the track 107,and the upper edges of the two tracks 117 and 110 also extend betweenthe rows of links 109. The tracks 117 and 118 are spaced from the uppertrack 107 a distance which is only slightly greater than the diameter ofthe rollers 108 of the chain 00, so that the tracks 107, 117 and 110hold the chain 00 between them.

Thus, the tracks 107, 117 and 118 slidably engage the chain 08, andpivotal movement of the track plate 111 on the bolt 112 causes the threetracks 107, 117 and 110 and the portion of the chain 00 between them tomove upwardly or downwardly relative to the sprocket 06. As shown insolid lines in FIG. 5, the teeth of the sprocket 06 extend upwardlybetween the two tracks 117 and 1 110 and into engagement with the chain08 when the plate 111 is pivoted downwardly, but when the plate 111 ispivoted upwardly to the dashed line position shown in FIG. 5, the chain00 is moved out of engagement with the sprocket 86.

To move the track plate 111 upwardly or downwardly, the track plate 111is connected to respond to angular movement of the tension arms 91 androd 92. A track link 122 (FIGS. 4 and S) is fastened to the track plate111 by screws 123 (FIG. 5) and extends generally downwardly therefrom toa location adjacent the upper side of the roller 103. Thus, when theroller 103 moves upwardly due to angular movement of the arms 91 in theclockwise direction as seen in FIG. 2, the roller 103 engages and movesthe link 122 upwardly to the dashed line shown in FIG. 5 where the chain88 is held out of engagement with the sprocket 86. However, subsequentangular movement of the arms 91 in the counterclockwise direction swingsthe roller 103 downwardly to the solid line shown in FIG. 5, and thelink 122 follows the movement of the roller 103 downwardly until thechain 88 drops into engagement with the sprocket 86. The sprocket 86then supports the chain 88 and the guides 107, 117 and 118 as the chaindrives the sprocket, and the roller 103 may move further downwardly awayfrom link 122. Thus, even though the link 122 cannot move furtherdownwardly, the arms 91 are able to swing further in thecounterclockwise direction (FIG. 2) in order to maintain tension on thefilm 20.

As previously mentioned, the chain 88 is connected to be driven by themain drive motor 18. The chain 88 extends from a drive sprocket 126(FIG. 1) on the shaft 21 and angles upwardly and toward the forward endof the machine, past the sprocket 86 and to a sprocket 127 which may ormay not be used to drive another part of the wrapping machine. From thesprocket 127, the chain 88 is trained about a pair of sprockets 128 and129 and then returns to the drive sprocket 126. The position of at leastthe sprocket 129 is preferably made adjustable so that the amount oftension on the chain 88 may be adjusted. The portion of the chain 88between the sprocket 126 and 127 is referred to herein as the slack side129 of the chain, and the portion of the chain between the sprocket 126and the idler sprocket 129 is referred to herein as the tight side 130of the chain. The slack side 129 of the chain 88 must have sufficientslack for the chain to be moved out of complete engagement with thesprocket 86, and the proper amount of slack may be attained by adjustingthe position of one or both of the sprockets 128 and 129.

Considering the operation of the wrapping machine, the film 20 from thesupply roll 29a is trained through the film feed mechanism 22 to thewrapping mechanism of the machine. The film may be trained around thestripper roll 66 by turning the stripper roll 66 in the clockwisedirection as seen in FIG. 2, such movement of the stripper roll 66 beingpermitted regardless of whether the sprocket 86 is turning because ofthe one-way clutch 87. The clutch 87 permits the stripper roll 66 to beturned in the clockwise direction (FIG. 2) ahead of the sprocket 86, butthe sprocket 86 may not be turned clockwise ahead of the stripper roll66. The film is looped about the tension roller 67 by swinging the arms91 in the counterclockwise direction (FIG. 2) and threading the filmabout the roller 67. The spring 94 connected to the rod 92 biases thearms 91 in the clockwise direction as seen in FIG. 2, but the film isprevented from being pulled out of the wrapping mechanism to the rightby the check valve 63 when the machine is not being operated, and by thewrapping mechanism during a wrapping cycle.

When the drive motor 18 is energized the wrapping mechanismautomatically pulls film to itself as needed during each wrapping cycle.The portion of the film extending between the stripper roll 66, thetension roller 67, and the idler roller 68 is referred to herein as areserve supply loop. As the film is pulled from this loop into thewrapping mechanism, the tension roller 67 and the tension arms 91 swingin the counterclockwise direction as seen in FIG. 2, thus depleting thequantity of film in the loop. Such movement swings the am 101 downwardlyand permits the link 122 to move downwardly, and the chain is permittedto drop into engagement with the sprocket 86. The main drive motor 18drives the chain 88 in the clockwise direction as seen in FIGS. 1 and 2,thereby turning the sprocket 86 and the stripper roll 66 in theclockwise direction. Such movement causes the stripper roll 66 to pullor strip additional film from the supply roll 63 which also turns due tothe pull on the film, thus replenishing the length of film in thereserve supply loop. The stripper roll 66 continues to strip film fromthe supply until the tension arms 91 swing clockwise sufficiently far tomove the link 122 up wardly and lift the chain 88 out of engagement withthe sprocket 86.

When the chain 88 engages the sprocket 86, additional film is notimmediately fed into the reserve supply loop because the film stretchesslightly and the inertia of the supply roll must be overcome. Since thewrapping mechanism continues to draw film from the reserve supply loop,the arms 91 will be swung to a generally vertical position and theroller 103 will move downwardly away from the link 122 before additionalfilm will be fed into the reserve supply loop. When the reserve supplyloop is replenished and the chain 88 is moved out of engagement with thesprocket 86, the inertia of the turning supply roll causes a smalladditional amount of film to be fed into the loop. The foregoing slightovertravel of the arms 91 in each direction of movement is advantageousbecause it reduces the frequency of engagement between the chain 88 andthe sprocket 86.

It will be apparent from the foregoing that an economical and sturdyfilm feed mechanism for a wrapping machine has been provided. The filmfeed mechanism is driven by the main drive of the wrapping machine and,consequently, a separate drive for the film feed mechanism is notrequired. In addition, the film feed mechanism may be inexpensivelymanufactured and does not include any parts which are subject toexcessive wear. The film feed mechanism responds quickly to a depletionof the reserve supply loop of film and it also responds quickly when thereserve supply loop has been replenished.

Iclaim:

1. In a wrapping machine for wrapping an article in a thin protectivefilm, the machine including means for supporting a supply of film, awrapping mechanism which draws film to itself as needed and folds thefilm about the article, and drive means for powering various mechanismsof the wrapping machine, the improvement of a film feed mechanismcomprising a rotatable stripper roll, movable tension means, film fromthe supply extending about said stripper roll and to said tension meansand then to said wrapping mechanism, said movable tension means beingbiased against the film to hold the film under tension and to form areserve supply loop in the film from which the wrapping mechanism drawsfilm, and clutch means for intermittently connecting said stripper rollto said drive means, said clutch means comprising a chain member whichis adapted to be connected to said drive means and to be continuouslymoving while the machine is in operation, a sprocket member connected tosaid stripper roller, and actuator means responsive to the position ofsaid movable tension means for moving said chain and sprocket membersinto meshing engagement and thereby rotating said stripper roll to pullfilm from the supply.

2. Apparatus as in claim 1, wherein said actuator means effectsengagement of said chain and sprocket members when said reserve supplyloop of film is depleted to a predetermined length and effectsdisengagement of said chain and sprocket members when said reservesupply loop of film is replenished to a predetennined length. I

3. Apparatus as in claim 1, and further including a one-way connectionbetween said stripper roll and said sprocket member.

4. Apparatus as in claim 1 wherein said chain has a slack side and atight side, said slack side extending adjacent said sprocket member,said actuator means being in sliding engagement with said slack side ofsaid chain and being operable to move said slack side out of engagementwith said sprocket.

5. Apparatus as in claim 4 wherein said slack side of said chain extendsacross the upper side of said sprocket, and the weight of said slackside is sufficient to move said slack side into engagement with saidchain.

6. In a wrapping machine for wrapping an article in a thin protectivefilm, the machine including means for supporting a supply of film, awrapping mechanism which draws film to itself as needed and folds thefilm about the article, and drive means for powering various mechanismsof the wrapping machine, the improvement ofa film feed mechanismcomprising a rotatable stripper roll, movable tension means, film fromthe supply extending about said stripper roll and to said tension meansand then to said wrapping mechanism, said movable tension means beingbiased against the film to hold the film under tension and to form areserve supply loop in the film from which the wrapping mechanism drawsfilm, and clutch means for intermittently connecting said stripper rollto said drive means, said clutch means comprising a driving member whichis adapted to be connected to said drive means and to be continuouslymoving while the machine is in operation, a driven member connected tosaid stripper roller, and actuator means responsive to the position ofsaid movable tension means for moving said driving and driven membersinto mutual engagement and thereby rotating said stripper roll to pullfilm from the supply, said driving member comprising a chain, and saiddriven member comprising a sprocket, said actuator means comprisingguide means slidably engaging said chain adjacent said sprocket andcontrolling the position of said chain relative to said sprocket, andmeans for moving said guide means in response to movement of saidtension means.

7. Apparatus as in claim 6, wherein said chain and said guide means arelocated generally above said sprocket, and said connecting means isadapted to lift said guide means and said chain upwardly to disengagesaid chain and said sprocket upon movement of said tension means in onedirection, and is adapted to permit said guide means and said chain todrop downwardly to engage said chain and said sprocket upon movement ofsaid tension means in the other direction.

8. Apparatus as in claim 7, wherein said connecting means comprises afirst member which is secured to said guide means, and a second memberwhich is connected to move with said movable tension means, said secondmember being adapted to move upwardly into engagement with said firstmember and lift said first member and said guide means upwardly, saidsecond member being further adapted to move downwardly out of engagementwith said first member.

9. Apparatus as in claim I, and further including high friction means onthe outer periphery of said stripper roll for frictionally engaging thefilm, said high friction means being made of silicone sponge.

10. in a wrapping machine for wrapping articles in a thin protectivefilm, the combination comprising means for supporting a supply of film,a rotatably mounted film stripper roll, movably mounted film tensionmeans, biasing means connected to said film tension means for urgingsaid film tension means in one direction, and a wrapping mechanism forwrapping an article in film and pulling film as needed while wrapping anarticle, the film extending from said supply, about said stripper roll,about said film tension means, to said wrapping mechanism, a pull onsaid film by said wrapping mechanism moving said tension means in theopposite direction against the force of said biasing means, acontinuously moving drive chain extending adjacent said stripper roll, asprocket connected to said stripper roll and adapted to rotate saidstripper roll when engaged by said chain, and

means extending between said tension means and said chain and adapted tomove said chain into and out of engagement with said sprocket uponmovement of said tension means, movement of said tension means in saidopposite direction in response to a pull on the film causing said chainto engage said sprocket and movement of said tension means in said onedirection in response to said biasing causing said chain to disengagesaid sprocket.

11. In a wrapping machine for wrapping articles in a thin protectivefilm, the combination comprising a wrapping mechanism for wrappingarticles in film and pulling film thereto as needed during each wrappingc cle, means for supporting a supply of film, and a feed mec amsm fordrawing film from the supply and feeding the film to the wrappingmechanism, said feed mechanism comprising a stripper roll, movable meansfor maintaining tension on the film and for forming a reserve supplyloop of film, continuously moving drive chain means, sprocket meansconnected to said stripper roll and adapted to be driven by said drivechain means when engaged thereby, and actuator means connected betweensaid movable means and one of said drive chain and sprocket means foreffecting engagement of said drive chain and sprocket means when saidreserve supply loop of film has been depleted to a predetermined lengthand for effecting disengagement of said drive chain and sprocket meanswhen said reserve supply loop of film has been replenished to anotherpredetermined length.

12. Apparatusas in claim 11, and further including a plurality offriction bands fastened to the outer periphery of said stripper roll,said friction bands being made of silicone sponge.

13. Apparatus as in claim 11, wherein said movable means is pivotallymounted, and said actuator means is connected to effect engagement anddisengagement of said drive chain and sprocket means upon pivotalmovement of said movable means.

14. In a wrapping machine for wrapping articles in a thin protectivefilm, the combination comprising a wrapping mechanism for wrappingarticles in film and pulling film thereto as needed during each wrappingcycle, means for supporting a supply of film, and a feed mechanism fordrawing film from the supply and feeding the film to the wrappingmechanism, said feed mechanism comprising a stripper roll, movable meansfor maintaining tension on the film and for forming a reserve supplyloop of film, continuously moving drive means, driven means connected tosaid stripper roll and adapted to be driven by said drive means whenengaged thereby, and actuator means connected between said movable meansand one of said drive and driven means for effecting engagement of saiddrive and driven means when said reserve supply loop of film has beendepleted to a predetermined length and for effecting disengagement ofsaid drive and driven means when said reserve supply loop of film hasbeen replenished to another predetermined length, said drive meanscomprising a roller chain and said driven means comprises a sprocketadapted to be rotated by said chain, and said actuator means comprises atrack slidably engaging said chain, and means connecting said movablemeans with said track and adapted to move said track and said chaintoward and away from said sprocket in response to movement of saidmovable means.

1. In a wrapping machine for wrapping an article in a thin protective film, the machine including means for supporting a supply of film, a wrapping mechanism which draws film to itself as needed and folds the film about the article, and drive means for powering various mechanisms of the wrapping machine, the improvement of a film feed mechanism comprising a rotatable stripper roll, movable tension means, film from the supply extending about said stripper roll and to said tension means and then to said wrapping mechanism, said movable tension means being biased against the film to hold the film under tension and to form a reserve supply loop in the film from which the wrapping mechanism draws film, and clutch means for intermittently connecting said stripper roll to said drive means, said clutch means comprising a chain member which is adapted to be connected to said drive means and to be continuously moving while the machine is in operation, a sprocket member connected to said stripper roller, and actuator means responsive to the position of said movable tension means for moving said chain and sprocket members into meshing engagement and thereby rotating said stripper roll to pull film from the supply.
 2. Apparatus as in claim 1, wherein said actuator means effects engagement of said chain and sprocket members when said reserve supply loop of film is depleted to a predetermined length and effects disengagement of said chain and sprocket members when said reserve supply loop of film is replenished to a predetermined length.
 3. Apparatus as in claim 1, and further including a one-way connection between said stripper roll and said sprocket member.
 4. Apparatus as in claim 1 wherein said chain has a slack side and a tight side, said slack side extending adjacent said sprocket member, said actuator means being in sliding engagement with said slack side of said chain and being operable to move said slack side out of engagement with said sprocket.
 5. Apparatus as in claim 4 wherein said slack side of said chain extends across the upper side of said sprocket, and the weight of said slack side is sufficient to move said slack side into engagement with said chain.
 6. In a wrapping machine for wrapping an article in a thin protective film, the machine including means for supporting a supply of film, a wrapping mechanism which draws film to itself as needed and folds the film about the article, and drive means for powering various mechanisms of the wrapping machine, the improvement of a film feed mechanism comprising a rotatable stripper roll, movable tension means, film from the supply extending about said stripper roll and to said tension means and then to said wrapping mechanism, said movable tension means being biased against the film to hold the film under tension and to form a reserve supply loop in the film from which the wrapping mechanism draws film, and clutch means for intermittently connecting said stripper roll to said drive means, said clutch means comPrising a driving member which is adapted to be connected to said drive means and to be continuously moving while the machine is in operation, a driven member connected to said stripper roller, and actuator means responsive to the position of said movable tension means for moving said driving and driven members into mutual engagement and thereby rotating said stripper roll to pull film from the supply, said driving member comprising a chain, and said driven member comprising a sprocket, said actuator means comprising guide means slidably engaging said chain adjacent said sprocket and controlling the position of said chain relative to said sprocket, and means for moving said guide means in response to movement of said tension means.
 7. Apparatus as in claim 6, wherein said chain and said guide means are located generally above said sprocket, and said connecting means is adapted to lift said guide means and said chain upwardly to disengage said chain and said sprocket upon movement of said tension means in one direction, and is adapted to permit said guide means and said chain to drop downwardly to engage said chain and said sprocket upon movement of said tension means in the other direction.
 8. Apparatus as in claim 7, wherein said connecting means comprises a first member which is secured to said guide means, and a second member which is connected to move with said movable tension means, said second member being adapted to move upwardly into engagement with said first member and lift said first member and said guide means upwardly, said second member being further adapted to move downwardly out of engagement with said first member.
 9. Apparatus as in claim 1, and further including high friction means on the outer periphery of said stripper roll for frictionally engaging the film, said high friction means being made of silicone sponge.
 10. In a wrapping machine for wrapping articles in a thin protective film, the combination comprising means for supporting a supply of film, a rotatably mounted film stripper roll, movably mounted film tension means, biasing means connected to said film tension means for urging said film tension means in one direction, and a wrapping mechanism for wrapping an article in film and pulling film as needed while wrapping an article, the film extending from said supply, about said stripper roll, about said film tension means, to said wrapping mechanism, a pull on said film by said wrapping mechanism moving said tension means in the opposite direction against the force of said biasing means, a continuously moving drive chain extending adjacent said stripper roll, a sprocket connected to said stripper roll and adapted to rotate said stripper roll when engaged by said chain, and means extending between said tension means and said chain and adapted to move said chain into and out of engagement with said sprocket upon movement of said tension means, movement of said tension means in said opposite direction in response to a pull on the film causing said chain to engage said sprocket and movement of said tension means in said one direction in response to said biasing causing said chain to disengage said sprocket.
 11. In a wrapping machine for wrapping articles in a thin protective film, the combination comprising a wrapping mechanism for wrapping articles in film and pulling film thereto as needed during each wrapping cycle, means for supporting a supply of film, and a feed mechanism for drawing film from the supply and feeding the film to the wrapping mechanism, said feed mechanism comprising a stripper roll, movable means for maintaining tension on the film and for forming a reserve supply loop of film, continuously moving drive chain means, sprocket means connected to said stripper roll and adapted to be driven by said drive chain means when engaged thereby, and actuator means connected between said movable means and one of said drive chain and sprocket means for effecting engagement of said drive chain and sprocket means when said reserve supply loop of film has been depleted to a predetermined length and for effecting disengagement of said drive chain and sprocket means when said reserve supply loop of film has been replenished to another predetermined length.
 12. Apparatus as in claim 11, and further including a plurality of friction bands fastened to the outer periphery of said stripper roll, said friction bands being made of silicone sponge.
 13. Apparatus as in claim 11, wherein said movable means is pivotally mounted, and said actuator means is connected to effect engagement and disengagement of said drive chain and sprocket means upon pivotal movement of said movable means.
 14. In a wrapping machine for wrapping articles in a thin protective film, the combination comprising a wrapping mechanism for wrapping articles in film and pulling film thereto as needed during each wrapping cycle, means for supporting a supply of film, and a feed mechanism for drawing film from the supply and feeding the film to the wrapping mechanism, said feed mechanism comprising a stripper roll, movable means for maintaining tension on the film and for forming a reserve supply loop of film, continuously moving drive means, driven means connected to said stripper roll and adapted to be driven by said drive means when engaged thereby, and actuator means connected between said movable means and one of said drive and driven means for effecting engagement of said drive and driven means when said reserve supply loop of film has been depleted to a predetermined length and for effecting disengagement of said drive and driven means when said reserve supply loop of film has been replenished to another predetermined length, said drive means comprising a roller chain and said driven means comprises a sprocket adapted to be rotated by said chain, and said actuator means comprises a track slidably engaging said chain, and means connecting said movable means with said track and adapted to move said track and said chain toward and away from said sprocket in response to movement of said movable means. 